Satnav systems, freqently blamed for lorries getting stuck in small country
lanes, now are accused accused of distracting drivers from the road ahead.

It appears that satnav systems are in danger of providing motorists with more information than they can cope with, an academic study has found.

The impact of this information overload was discovered in a series of experiments carried out by Polly Dalton, from the department of psychology at Royal Holloway College, London and Pragya Agarwal, of Lancaster University.

The more information volunteers received the faster they drove. Researchers also found the number of steering adjustments increased at the same time.

"What is interesting is that people were able to follow one simple instruction without any significant impact on their driving,” Dr Dalton said.

"But as soon as they had to remember a compound instruction, consisting of two sequential directions, we began to notice a difference in their driving ability."

Dr Dalton went on: “There is a need to make these instructions as simple as possible.

”You need to deliver the information in as straightforward and simple chunks as possible

“There is an issue about how much information a brain can retain at one time especially when you are trying to perform another task such as driving.

“The potential danger is that a driver who is memorising a large chunk of information can be distracted from the road ahead.”

Other studies have also raised doubts about the benefits of satnav, which are not only one of the best selling consumer gadgets but are now becoming being built into on an increasing number of cars.

One survey found that 19 per cent of motorists admitted they had been distracted by their satnav system, two per cent more than those whose attention wandered when they had a map on their lap.

“People can get flustered,” said Andrew Howard, the AA’s head of road safety. “It’s just like having your wife alongside you telling you to turn sharp right and fork left.

"You are still better off having some instructions rather than trying find street names on signs which can be 20 feet up or a couple of feet from the ground or not there at all.

“We should always remember that if somebody needs satnav, they will need an alternative if it is not provided and looking for street signs can draw your eye on the road ahead.”

Robert Gifford, Executive Director of the Parliamentary Advisory Council for Transport Safety, added: “Driving is a complex task that needs our full attention.

“If instructions from a satnav become a distraction, drivers will have less ability to maintain their concentration on what is happening around them. The crucial issue is to design systems that will support the driver rather than confuse him.”

A spokesman for TomTom, which has supplied 60 million motorists across the world, defended the devices.

"Independent tests carried out on behalf of TomTom indicate that driving with a dedicated navigation device improves driver concentration and focus," he said.

"The research carried out by Dutch organization TNO found that driving with a navigation device had a positive impact on driver awareness, reduced driver stress and workload, and had a positive effect on driver behaviour in general."